1. Field of the Invention
The present invention relates to liquid ejection heads and liquid ejection apparatuses, and more specifically, relates to a parts arrangement in an electrical wiring substrate for supplying an electric signal to a printing element substrate for ejecting liquid, such as ink, in the liquid ejection head.
2. Description of the Related Art
In the liquid ejection head, an electrothermal conversion element is used as a printing element that generates energy for ejecting liquid. The electrical wiring substrate for supplying an electric signal to this electrothermal conversion element is provided corresponding to the printing element substrate having the electrothermal conversion elements arranged therein.
Japanese Patent No. 4757011 describes a long line-type liquid ejection head including a plurality of printing element substrates arranged on a support substrate. In this liquid ejection head, the plurality of printing element substrates is arranged in a staggered form along the direction of arranging their ejection ports. In the electrical wiring substrate used here, a single electrical wiring substrate has respective openings for incorporating the plurality of printing element substrates. Moreover, US Patent Laid-Open No. 2005/0162466 describes a liquid ejection head including a plurality of head modules mounted on a support member. In the individual head module, a printing element substrate is mounted on a flow path member and an individual electrical wiring substrate is provided around the printing element substrate.
However, the arrangements of the electrical wiring substrate described in Japanese Patent No. 4757011 and US Patent Laid-Open No. 2005/0162466 have a problem that particularly the position of the printing element substrate may deviate from a desired position due to a sealing member for sealing an electrical connecting portion between the electrical wiring substrate and the printing element substrate.
Specifically, in manufacturing the liquid ejection head, first, the printing element substrate and the electrical wiring substrate are bonded and fixed onto the support member, and these substrates are electrically connected to each other by using wires. Then, a sealing agent is applied to this connecting portion and the resulting portion is heated to cure the sealing agent. Furthermore, after curing the sealing agent, the liquid ejection head is taken out from a heating furnace and cooled. The electrical wiring substrate expands and contracts due to heating and cooling for curing the sealing agent in such a manufacturing process. That is, during heating, the sealing agent is cured in the state where the electrical wiring substrate extends, and the electrical wiring substrate will contract due to the subsequent cooling. In this process, the support member and the printing element substrate experience the stresses of extension and compression and thereby the position of the printing element substrate may vary. Such a liquid ejection head including the printing element substrate whose position has deviated might cause a problem, for example, that the printing image quality degrades.